Drying apparatus



19344 E. BLEIBLER v 1,985,219 7 I DRYING APPARATUS Filed April 29.- 1930 Patented Dec. 18, 1934 DRYING APPARATUS Ernest Bleibler, Winterthur, Switzerland, assignor to Sylvania Industrial Corporation, Fredericksburg, Va., a corporation of Virginia Application April 29, 1930, Serial No. 448,337

' In Germany May 2, 1929 3 Claims.

The invention relates to drying apparatus for cellulose products, more particularly films, skins, strips, webs and the like derived for instance from an aqueous'solution of cellulose, for in- 5 stance sodium xanthate cellulose. The invention is particularly suitable for plants in which the cellulose or similar products obtained from those solutions pass in a continuous manufacturing process from the precipitation baths, cleaning baths and the like on to the drying rollers or cylinders.

The object of the invention is to provide a machine in which the drying process may be accurately adjusted and which supplies an excellent smooth material of good appearance free from scratches or streaks or other faults which render the material unsightly and reduce its value. It has been ascertained that the shrinkage losses during the drying process are very small in the improved apparatus, more particularly in the direction of the width of the film.

By the improved arrangement according to the invention it is possible to avoid in the roller drying apparatus the difilculties arising from the iact that the strip of cellulose in the wet state as indirectlyor directly obtained from the treatment baths has little strength and thus easily breaks during the drying process if undue stresses develop. Such stresses may be caused by shocks occurring in the drive of the dryer rollers. for instance in consequence of worn out gear wheel drives.

, In apparatus with top rollers riding loosely on the cellulosic films stresses may be also caused by the cellulose film being squashed by the weight of the rollers resting upon it, and also by the fact that the peripheral velocities of rollers fol I lowing each other differ from one to the next so that the strip is obliged to slide upon the rollers in order to adapt itself to the speed fluctuations. According to this invention in a drying apparatus for drying films, strips and the like of cellulose, more particularly of regenerated cellu-v lose, the train of drying rollers or cylinders supporting the film or the like alternately on one side and the other side of the latter andimmediately on the drying rollers, consists of two tiers of rollers one above the other and in addition is sub divided into groups, each group comprising; an odd number of rollers 01 one tier and an even number of rollers of the second tier lying between the rollers 01 the first tier, an end roller of one group being common to an adjacent group and each group being individually power driven.

Irregularities oi the drive, noticeable in speed differences of one roller to the next, are compensated or neutralized, and the rollers ot the train of rollers or the group in'questionare forced to run synchronously or with equal velocity no mat-e ter to what fluctuations or thrusts one or the 8 other of the individual drives present is subjected to. Thus the diflerences in speed in belt drives caused by belt slip may be effectively eliminated. I

The arrangement according to my invention in 10 which the individual rollers or some number of the rollers stand simultaneously under the control of .a plurality of drives may be realized in various ways.

Preferably a belt drive will be employed as 15 one of the drives in view of the fact that, apart from the slip, the belt drive is substantially free from shocks or thrusts, and also permits or a convenient'connection of the differently grouped driving wheels. I

In a preferred embodiment of the invention, the groups consist of three rollers, via, one lower roller and two upper rollers and the groups are individually driven by a belt drive common to all rollersof the group and being driven from a separate source of power, driving means being arranged for coupling said groups to each other, or preferably the top rollers being common to the adjacent individually driven group.

In further preferred embodiments of the invention the rollers oi the plant or train'ot drying rollers or cylinders are subdivided into groups, each group being equipped with a drive of its own and one roller at least being common to two adjacent groups; In a particularly suitable 35 design of this type each group consists of an odd number of rollers, preferably two top rollers and one bottom roller, and each outer top rolleris common to the adjacent groups. 1

In the drawings affixed to my specification and forming partthereof a number ofembodiments of my inventionv are illustrated by way of example. I It will be readily understood, however, that my invention. is by no means limited to these constructions and that the scope of my invention and the ambit of my appended claims extends to any construction incorporating the broad principle underlying my invention..

In the drawings'Fig. 1 shows diagrammatically 50 a train or plant of rollers well known in the art of drying pellicles, strips, films and the like of cellulose or similar products. Fig. 2 illustratesan embodiment of my tion'in side elevation,

inven f Fig. 3 is an elevation from the drive side of the arrangement according to Fig. 2 and Fig. 4 represents two rollers of the arrangement according to Figs. 2 and 3 with their drives in front'elevation- Referring to Fig. l of the drawings it will be observed that the strip or band of cellulose of an indefinite length travels over the rollers of the train or plant of rollers. In Figs. 2 to 4 this band or film to be dried has been omitted for the sake of clearness. The band is here passed over the rollers preferably in the manner shown in Fig. l.' It will be understood, however, that the strip or band may be guided in a different manner, for instance through between the rollers.

From a vat or tank 12, which according to the process of manufacture contains a cleaning,

hardening or other bath, for example a band or strip of cellulose 11,.isgwithdrawn over the drying rollers 14, 15 and finally reaches the winding-up reel 17. r

,In the embodiment illustrated in Fig. 2 in side-elevation, in Fig. 3 in plan, and in Fig. 4 in front-elevation, the, belt drives 40, 41 drive by means of the belts 42, 43 groups consisting of three roll members, viz: the bottom rollers 44 or 45 as well as the top rollers 46, 47. On the trunnions of the rollers or cylinders 44 or 45 respectivelythere is keyed a pulley 50 or 51 respectively, while on the trunnions of the top rollers there are mounted two pulleys each 52, 53 one of which, for instance, 52 pertains to the drives 40, 42, the other 53 to the drives 41, 43. All the top rollers are thus directly and the bottom roller indirectly under the control of two drives simultaneously so that undesired mutual movements of the rollers of adjacent groups as well as of the train of rollers or sections of it are entirely precluded. The roller groups may at any time is ensured still further considerable advantages are realized by the improved arrangement according to my invention. Thus the top roller and the bottom roller may be so securely journaled that no relative motion need be feared, and it is possible to adapt the spacing of the rollers to the conditions prevailing in each individual case. The rollers may be arranged closely together or preferably at such distances apart that when the film breaks it is-able to coil itself up on any one of the rollers without braking the rollers or the entire train of rollers, and. that on the other hand the rollers maybe easily cleaned and the cellulose film threaded through between the rollers without the danger that the hand of the operator might be gripped by the rollers and drawn intothe machine.

A still further advantage of the rollers journaled'in stationary bearings is that the top rollers as well as the bottom rollers may conveniently 7 with short trains or plants of rollers consisting of a few rollers only- A still further advantage over the arrangement in which the top rollers rest upon the bottom rollers resides in the fact that, as already pointed out, the cellulose film to be dried is relieved of the weight of the top roller in case this roller rests directly upon the bottom roller or in case the top roller rests loosely on the bottom roller and is maintained at a short distance from the bottom roller by means of spacing ring; the rapid wear of these rings running in the drive state is efiectively avoided. The films to be dried run uniformly and smoothly round the rollers, cylinders or drums without any relative movement between film and roller apt to cause scratching or scoring of the surface of the film and thus to aifect its appearance adversely.

It will be understood that the invention is not limited to the embodiments described and illustrated by way of example and that various structural changes and modifications may be made without departing from the spirit of my invention, and I desire therefore that the appended claims should be construed in the light of prior knowledge.

Instead of the belt drives shown in the drawings gear drives might thus be provided, since now in consequence of the multiple drive of the individual rollers or groups of rollers according to my invention shocks or thrusts on the indi-.

vidual rollers can no longer occur in such drives and, as already described thespeeds of the individual rollers are controlled in a 'perfect'manner while in the known customary drives of the roller or 'of entire trains of rollers and coupling of these rollers merely by the film to be dried a control of the speed, particularly in trains consisting of a great number of rollers, is quite impossible. Slip losses of the belt or other drives, shocks caused by wear and inaccurate adjustment of gear wheels, cannot possibly be avoided in the known drives and greatly reduce the quality of the final product.

I claim as my invention:-

1. In a drying apparatus for drying films, strips and the like of cellulose, more particularly of regenerated cellulose, the combination of a train of drying rollers adapted to support the film alternately on one side and on the other side of the latter and immediately on the surfaces an adjacent group and each group being individually power-driven.

drying rollers, said train comprising two superimposed tiers of rollers and being subdivided into groups of three rollers, each group comprising one lower roller and the two upper rollers adjacent thereto, each groupbeing individually driven by a belt drive common to all rollers of said group and being driven froma separate.

source of power, and driving means for coupling said groups to each other. l

3. In a drying apparatus for drying films, strips and the like of cellulose, more particularly of retwo upper rollers adjacent thereto, each group generated cellulose, the combination 01. a train of drying rollers adapted to support the film alternately on one side and on the other side of the latter and immediately on the surfaces of the drying rollers, said train comprising two superimposed tiers of rollers and being also subdivided into a plurality of groups 0! three rollers each, each group comprising one lower roller and the being individually driven by a belt drive common to all rollers of said group and being driven'from a separate source of power, at least one of the top'rollers of each group being common to the 5 adjacent individually driven group.

ERNEST BLEIBIJER. 

